1. Field of the Invention
This invention relates to air bag restraint systems for vehicles and, more particularly, to such air bag restraint systems which are covered by a cover assembly for concealing the air bag restraint system in a vehicle passenger compartment as part of the instrument panel.
2. Description of Related Art
Various air bag restraint systems are known in which a cover assembly covers the air bag restraint components prior to deployment of an air bag into the vehicle passenger compartment.
U.S. Pat. No. 3,622,176 discloses a cover with a perforated outer skin. The problem with such an arrangement is that the weakened sections are visible and thus do not fully conceal the underlying air bag restraint system. Furthermore, such systems depend upon the force of the inflated air bag to tear the cover to form a deployment opening therein. Such tearing can at times hinder deployment in an undesirable manner.
U.S Pat. No. 4,097,064 discloses a cover assembly which carries a cutter to pierce the outer skin of the cover assembly. However, this arrangement requires separate inertially responsive shields for protecting the air bag during its deployment
U.S. Pat. No. 4,246,213 discloses a cover assembly that includes a cover having weakened sections in the outer shell or skin of the cover assembly. This arrangement depends upon the tearing of the outer skin at the weakened sections for air bag deployment and presents the same disadvantages as in the case of the '176 patent.
U.S. Pat. Nos. 5,080,393 and 5,082,310 disclose cover assemblies in which substrates have a potential to fragment during airbag deployment.